Re: [PATCH v6 2/6] arm64: ptrace: allow tracer to skip a system call

Russell King - ARM Linux
2014-09-01T11:48:06Z

On Wed, Aug 27, 2014 at 02:55:46PM +0900, AKASHI Takahiro wrote:
> 1)
> setting x0 to -ENOSYS is necessary because, otherwise, user-issued syscall(-1) will
> return a bogus value when audit tracing is on.
>
> Please note that, on arm,
> not traced traced
> ------ ------
> syscall(-1) aborted OOPs(BUG_ON)
> syscall(-3000) aborted aborted
> syscall(1000) ENOSYS ENOSYS

Two points here:

1. You've found a case which causes a BUG_ON(). Where is the bug report
for this, so the problem can be investigated and resolved?

2. What do you mean by "aborted" ?

Please, if you find a problem with 32-bit ARM, report it. Don't hide it,
because hiding it can be a security issue or in the case of BUG_ON(), it
could be a denial of service issue.

As you're part of Linaro, I would have thought you'd be more responsible
in this regard - after all, Linaro is supposed to be about improving the
ARM kernel... Maybe I got that wrong, and Linaro is actually about
ensuring that the ARM kernel is stuffed full of broken features?

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